Computing systems for generating real-time images have been in widespread use for well over a decade. However, demands for improvement continue to challenge the technology. While prior systems have been effectively used in training applications, a need continues for improved realism and flexibility. For example, visual displays for flight simulator training systems have been extremely useful and effective. However, in such applications a need continues for greater realism.
To consider specifics, a need has existed for a system to project real-time, computer-generated images of a dome, rather than a mosaic of flat surfaces. A dome screen offers several advantages. It may be seamless and, therefor, easier to build and watch. Furthermore, it does not cause discontinuities in the slewable target projector image. Conversely, traditional screens comprising a mosaic of flat surfaces have certain disadvantages. For example, screens compel the use of a separate channel for each flat surface. A single curvilinear image generator offers the advantage of projecting a single channel onto a section of a dome within the limitations of image capacity.
Prior systems have been proposed for curvilinear projection. However, such systems generally have involved a two step process retaining the operation of perspective division then applying distortion correction. The technique does not allow fields of view from a single channel to approach 180 degree projection because of the required degree of numerical precision to preserve the integrity of the display at edges.
Consequently, a specific need exists for an improved visual system utilizing real-time, computer-image generation which is economical and effective to project images onto various curvilinear surfaces including cylinders and spheres with projection fields of view up to 180.degree.. It is important that such a system correct distortions created in the optics or which result from the projector being mounted off axis, all with relatively minimal image and system capacity degradation.
In general, the system of the present invention is an improved form of a real-time, computer-generated image apparatus. With reference to prior art systems, the improvement of the present invention resides in the structure generally referred to as the image processor. Specifically, the segmenting and mapping operations in the image processor of the present invention replace the conventional perspective divider and accomplish the improvements and objectives mentioned above. Accordingly, the improved system is capable of projecting images onto a variety of curvilinear surfaces including cylinders and spheres with wide fields of view and incorporating optical or off-axis correction.